The Java Community Process is lacking in openness, thereby preventing the creation of an independent open source Java implementation, the Apache software foundation charged in an open letter addressed to Sun Microsystems.

The Apache Foundation is sponsoring the open source project Harmony that aims to create an implementation of the desktop version Java SE 5 under an open source license. The project marks the first desktop Java implementation by a non-commercial entity.

The problems revolve around the so-called Java Compatibility Kit (JCK), a tool that is required to verify that third party Java SE 5 implementations with the official standard. The JCK software is governed by a license that essentially limits the applications for the open source Java implementations can be used. The software for instance couldn't be used in enclosed cabinets such as information kiosks or X-ray machines at airports, Apache said.

"These restrictions are totally unacceptable to us," Geir Magnusson, vice president of the Apache Harmony project wrote in his letter. He added that the restrictions directly contradict some of the principles behind the Java Community Process. The JCP essentially governs the Java technology.

"The situation we are facing is grossly in conflict with the basic IP philosophy of the JCP, the concept of Java as an open standards-based ecosystem, Sun's contractual obligation as a specification lead under the Java Specification Participation Agreement. […] It is contrary to both the spirit and letter of open source, the respect of which is a key element in Sun's stated business strategy."

Magnusson said that he has been discussing the limitations since August last year, but was unable to make any progress.

Although Sun ultimately owns the Java technology, the company provides licences to third party developers. Commercial vendors such as BEA and IBM are charged a fee and have to pledge that they won't enforce their intellectual property against any users of Java technology. Sun has previously committed to providing Harmony free license to the technology.

Since the Harmony project got started, Sun has released its own Java SE 5 implementation under the General Public License. The company also has been critical about the usefulness of the project.

Apache however has said that it will continue working on the project.

Sun Microsystems in response to the open letter said that it is working to " make the Java platform accessible to the GNU/Linux community as quickly as possible", but cautioned that this process will take more time.